It is known to provide a communications interface for a computer output printer with interchangeable plug in modules that provide different communications protocols, such as RS232, Centronics etc. See U.S. Pat. No. 4,426,166 issued Jan. 17, 1984 to Bowling. It is also known to provide a printer with a communications interface having a plurality of input ports so that the printer can be shared by a number of users. For example, see the Multiuser Interface Option provided for the MT910 printer sold by Mannesmann Tally Corp., Mississauga, Ontario. The Multiuser Interface Option is a plug-in card that can be configured by the users to allow up to 4 users employing RS-232 serial input protocol to emulate any one of a variety of other manufacturers printers. A shortcoming with this interface is that it is restricted to one communications protocol (RS-232) and that while one user is using the printer, another user must wait, thereby decreasing the efficiency of the computer that is waiting to use the printer. A partial solution to this problem for a number of users using a single printer, is a multi-port print buffer card. An example of such a multi-port print buffer card is the JetShare.TM. print buffer card sold by INMAC Corp. Santa Clara, Calif. for use in the Hewlett-Packard LaserJet II.TM. printer and having four serial and one parallel input ports. Although baud rates for each port can be set independently from the front control panel of the printer, emulation of other manufacturers' printers is not provided, so that all of the computers sharing the printer must be programmed to operate that particular printer. The object of the present invention is to provide a printer with a communications interface that overcomes the shortcomings noted above.